I stumbled across this product on a shoptour some months ago and had to find out more, writes Nathan Hill.

The concept is straightforward enough. Sintered glass has been long used as a biological media and many of us will know it after examining the contents of our external canister filters.

However, this offering comes with two differences. The first is that it floats, as opposed to just sinking and being immobile. The second is that it is coated in slow-release montmorillonite clay.

The floating aspect means it can be used in a variety of home-made filters that exploit this behaviour, which is exactly as I first saw it.

At the store in question, inverted drink bottles with holes at the top and an air line feed at the base kept the balls in constant motion, as well as oxygenated and fed with passing water and nutrients.

It behaves much like Kaldness K1 media in the way it moves, just without the sludgy bacterial slime all over it.

It’s as porous as a filter media gets and, if you so invest, crack one open to see the deep, 'Malteser'-like structure, where your bacteria will reside. It’s fascinating stuff.

Pond keepers will probably want to view this as an alternative or complement to existing floating media, but aquarium keepers should give this stuff a closer look and see if they can fit it into their plans anywhere.

I’m going to be making one of my own 'biological fluid beds' out of a bottle sometime soon, but I’m extremely keen to find out how other aquarists adapt the floating behaviour to suit their own means.

It’s great — if occasionally slightly rattly — inside a standard canister filter, but I can’t help but think I’m not using it quite to its full potential just yet.

Verdict

This is a new take on an old product, I think it has some real mileage and might be just the thing to maximise biological capacity in limited space, such as heavily-stocked fish houses.